248 PATHOGENIC BACTERIA. 



importance in surgery and in surgical bacteriology, yet 

 it is one which it is impossible to remove. We carry it 

 constantly with us upon our skins. 



Staphylococcus Epidermidis Albus. 



Welch has described, under the name Staphylococcus 

 epidermidis albus, a micrococcus which seems to be habit- 

 ually present upon the skin, not only upon the surface, 

 but also deep down in the Malpighian layer. He is of 

 the opinion that it is the same organism which is familiar 

 to us under the name of Staphylococcus pyogenes albus, 

 but in an attenuated condition. If his opinion be correct, 

 and we have seated deeply in our derm a coccus which 

 can at times cause abscess-formation, the conclusions of 

 Robb and Ghriskey, that sutures of catgut when tightly 

 drawn may be a cause of skin-abscesses by predisposing 

 to the development of this organism, are certainly justi- 

 fiable. 



Not only does the coccus occur in the attenuated form 

 described, but we have very commonly present upon the 

 skin, generally as a harmless saprophyte, the important 

 Staphylococcus pyogenes albus, which is a common cause 

 of suppuration. 



Staphylococcus Pyogenes Albus. 



Although, as stated, the Staphylococcus pyogenes albus 

 is a common cause of suppuration, it rarely occurs alone, 

 the studies of Passet showing that in but 4 out of 33 cases 

 which he investigated was this coccus found by itself. 

 When pure cultures of the coccus are injected subcu- 

 taneously into rabbits and guinea-pigs, abscesses some- 

 times result ; sometimes there is no result. Injected 

 into the circulation of these animals, the staphylococci 

 sometimes cause septicemia, and after death can be found 

 in the capillaries, especially of the kidneys. From these 

 illustrations it will be seen that the organism is feebly 

 pathogenic. 



In its vegetative characteristics the Staphylococcus 



